Herbaceous Legumes Research Articles

Dry Matter Production, Nutrient Cycled and Removed, and Soil Fertility Changes in Yam-Based Cropping Systems with Herbaceous Legumes in the Guinea-Sudan Zone of Benin.

Traditional yam-based cropping systems (shifting cultivation, slash-and-burn, and short fallow) often result in deforestation and soil nutrient depletion. The objective of this study was to determine the impact of yam-based systems with herbaceous legumes on dry matter (DM) production (tubers, shoots), nutrients removed and recycled, and the soil fertility changes. We compared smallholders' traditional systems (1-year fallow of Andropogon gayanus-yam rotation, maize-yam rotation) with yam-based systems integrated herbaceous legumes (Aeschynomene histrix/maize intercropping-yam rotation, Mucuna pruriens/maize intercropping-yam rotation). The experiment was conducted during the 2002 and 2004 cropping seasons with 32 farmers, eight in each site. For each of them, a randomized complete block design with four treatments and four replicates was carried out using a partial nested model with five factors: Year, Replicate, Farmer, Site, and Treatment. Analysis of variance (ANOVA) using the general linear model (GLM) procedure was applied to the dry matter (DM) production (tubers, shoots), nutrient contribution to the systems, and soil properties at depths 0–10 and 10–20 cm. DM removed and recycled, total N, P, and K recycled or removed, and soil chemical properties (SOM, N, P, K, and pH water) were significantly improved on yam-based systems with legumes in comparison with traditional systems.

Methanogenic potential of forages consumed throughout the year by cattle in a Sahelian pastoral area

Methane (CH4) emission from ruminants in African pastoral systems may be affected by intake and type of plants, which vary highly between rainy and dry seasons. In each of two sites located in the semiarid Sahelian area of Senegal, three Gobra zebus were monitored throughout 1 year. A representative sample of their diet was obtained once every month. Diet was mainly composed of grasses, herbaceous legumes, tree and shrub foliage and pods, and dried forage residues. CH4 production and volatile fatty acid (VFA) concentration, which reflects VFA production, were determined in vitro. Crude protein, neutral detergent fibre (NDF) and acid detergent fibre were measured by near-infrared spectrophotometry. CH4 production varied between 24.6 and 35.2 mL/g forage dry matter (DM), being minimal in August (rainy season) and maximal in February (dry season). Seasonal difference disappeared when CH4 was expressed in mL/g NDF. The acetate : propionate ratio varied in the same way as CH4 (3.2 and 4.6 in August and February, respectively); VFA concentration was minimum in March and maximum in September (69.2 and 77.4 mmol/L, respectively). CH4 production was closely related to dietary NDF content (r = 0.82) and to acetate : propionate ratio (r = 0.96). For six successive periods (February to July), plant categories constituting the diet were incubated separately. Reconstituting the CH4 production and VFA concentration in the diet on the basis of the proportion of plant components gave values similar to those of the global diet (33.4 and 34.2 mL CH4/g DM and 75.9 and 70.9 mmol VFA/L, respectively). This result suggests the absence of interaction among plant components on rumen fermentation.

Botanical composition of Caatinga rangeland and diets selected by grazing sheep

Sheep dietary selection from species-diverse Caatinga rangeland of semi-arid northeastern Brazil has not been documented. This study examined the botanical composition of the available forage and diets of Dorper x Saint Ines ewes on thinned Caatinga over-seeded with Cenchrus ciliaris and Urochloa mosambicensis . Sixty-three species from 23 families, dominated by shrubs and short trees of low forage nutritive value, were identified in the vegetation. The botanical composition revealed, on average, high presence of 29.2% Malvaceae and 13.0% C. ciliaris . Using the microhistological technique, sheep showed, on average, 59.6% preference for dicotyledons throughout the year. However, selectivity indexes indicated, on average, greater selection for Poaceae during the rainy season (1.5) and for dicotyledons in the dry season (1.8) with a year-round aversion for Malvaceae (0.3). These findings suggest that Caatinga vegetation management should include Malvaceae thinning and greater incorporation of grasses and herbaceous legumes to improve rangeland carrying capacity. Keywords: Brazil, continuous stocking, dietary selection, microhistological technique, principal components. DOI: 10.17138/TGFT(4)71-81

Expression of amphicarpy in Vigna lanceolata morphotypes and their hybrids and implications for cultivar development

Amphicarpy is an adaptation that enhances persistence under various environmental stresses, including heavy grazing, through the production of both aerial and underground seeds on the same plant. The trait occurs in several Australian endemic tropical herbaceous legumes, including Vigna lanceolata. The objective of the current research was to compare aerial and underground reproductive structures in six amphicarpic morphotypes of V. lanceolata (four perennials and two annuals), and in hybrids among these morphotypes and also with a seventh, non-amphicarpic perennial morphotype. The aim was to establish how easily the trait might be manipulated in a breeding program to develop improved amphicarpic cultivars, for ley and forage purposes. In the four amphicarpic perennials, the underground fruiting structures formed on leafless underground stems or rhizomes, and in all four, amphicarpy was habitual, i.e. individual plants routinely developed both aerial and underground fruiting structures. In the two annuals, the underground fruiting structures developed on specialised axillary geotropic stems that arose along the prostrate aerial stems and penetrated the soil or leaf litter. One of the annuals exhibited habitual amphicarpy, whereas the other was opportunistic, in that the underground fruiting structures developed only where aerial stems became covered with soil or leaf litter. F1 hybrids between the two annual morphotypes exhibited habitual amphicarpy, indicating dominance of habitual over opportunistic amphicarpy. F1 hybrids between the four perennial amphicarpic morphotypes were all amphicarpic, reflecting the similar expression of the trait in these forms. By contrast, when these four were crossed with the non-amphicarpic perennial, none of the viable F1 hybrids exhibited amphicarpy, suggesting dominance for non-expression. Many of the perennial F1 hybrids were self-sterile, but in the hybrids that were at least partially fertile, many more geocarpic than aerial seeds were produced, raising the possibility that in the wild, amphicarpy may facilitate the persistence of chance natural outcrosses that might otherwise not survive. The results suggested that it would be feasible to develop amphicarpic annual and amphicarpic perennial cultivars for, respectively, ley and forage purposes.

Temperature and humidity of soil covered with perennial herbaceous legumes in the semiarid region of Minas Gerais, Brazil

Agricultural sustainability of areas in semiarid region, is directly related to soil management, emphasizing especially the continuous coverage strategy. In this sense, this study aimed to evaluate the influence of perennial legumes on soil coverage, temperature and moisture in the semiarid region of Minas Gerais, Brazil. The study used a randomized blocks experimental, with 9 m 2 , design and treatments consisted of bare soil cultivated with the following legumes: tropical kudzu ( Pueraria phaseoloides ), calopo ( Calopogonium mucunoides ), perennial peanut ( Arachis pintoi ), perennial soybean ( Glycine wightii ) and stylosanthes Campo Grande (mixture of Stylosanthes capitata and Stylosanthes macrocephala ), with four replications. Soil coverage, temperature and moisture rates were evaluated. Due to the soil protection provided by the biomass production, the use and management of cover plants in semiarid region of Minas Gerais contributed to the temperature reduction and to the conservation of soil moisture, both essential for the agricultural production in this region. Calopo, tropical kudzu and perennial peanut provided greater soil coverage and, consequently, they provided greater reduction in temperature and higher moisture retention in soil. In more advanced stages of the cycle, the perennial soybean also provided good soil coverage, temperature reduction and moisture retention in the soil.

Stoichiometric Characteristics of Carbon, Nitrogen, and Phosphorus in Leaves of Differently Aged Lucerne (Medicago sativa) Stands.

Element concentration within a plant which is vital to function maintenance and adaptation to environment, may change with plant growth. However, how carbon (C), nitrogen (N), and phosphorus (P) vary stoichiometrically with stand growth, i.e., ages or cuts, was still untouched in perennial species. This study tested the hypothesis that lucerne (Medicago sativa) C:N, C:P, and N:P should change with stand age and cut. Leaf C:N, C:P, and N:P changed with stand age, showing various trends in different cuts of lucerne. Generally the greatest stoichiometric ratios were measured in 8 year stand and in the second cut. They were affected significantly and negatively by total N and P concentrations of leaf, but not by organic C concentration. There were significantly positive correlations among leaf C:N, C:P, and N:P. However, leaf C:N, C:P, and N:P were hardly affected by soil features. Conclusively, lucerne C, N, and P stoichiometry are age- and cut-specific, and regulated mainly by leaf N, P concentrations and stoichiometry. There are few correlations with soil fertility. To our knowledge, it is the first try to elucidate the stoichiometry in the viewpoint of age and cut with a perennial herbaceous legume.

How does the seed fate of Crotalaria podocarpa DC, a highly competitive herbaceous legume in arid rangelands, contribute to its establishment probability?

Plant recruitment can be constrained by processes shaping its seed fate, such as pre- and post-dispersal seed predation, while facilitated by higher seed production and more effective dispersal. These activities are controlled by specific predator and disperser guilds that respond to different microsite conditions such as vegetation density with varying predation and removal rates. In Namibia's arid rangelands, the native, annual herbaceous legume Crotalaria podocarpa has considerably increased after several years of elevated rainfall, thereby reducing density and vitality of economically important fodder grasses. To investigate whether this proliferation entails the risk of a permanent establishment, we studied pre- and post-dispersal seed predation, as well as primary and secondary seed dispersal of the legume and quantified the impact of different predator groups on post-dispersal seed removal. We experimentally excluded (i) neither vertebrates nor invertebrates, (ii) birds, (iii) vertebrates (birds and rodents), and (iv) vertebrates and large invertebrates on plots with different C. podocarpa density (0–35% cover). Seed predation was mainly caused by invertebrates, with 30% pre-dispersal seed predation in pods and up to 90% post-dispersal seed removal for free seeds on the ground which is the most persistent seed stage. C. podocarpa density did not affect post-dispersal seed removal or secondary seed dispersal. As main dispersal mode for the study species explosive dehiscence was identified, with seeds reaching dispersal distances of up to 4m, while wind or rolling dispersal played a minor role. Subsequent secondary dispersal by animals accounted for dispersal distances up to 19m. Our findings highlight the combined effects of pre- and post-dispersal seed predation to determine the total seed fate. With a contribution of about 370 seeds m−2 to the species persistent soil seed bank, seed numbers seems to be more important for C. podocarpas vagility than the species dispersal ability. Supplemented by seedling fate and adult mortality, this data can contribute to reliably predict the risk of a further spread of the species.

ESTABLISHMENT TECHNIQUES FOR TROPICAL LEGUMES IN THE UNDERSTORY OF A EUCALYPTUS PLANTATION

This study evaluated establishment methods for a mixture of herbaceous forage legumes [Centrosema acutifolium, Clitoria ternatea, Pueraria phaseoloides, Stylosanthes Campo Grande (Stylosanthes capitata + S. macrocephala), Calopogonium mucunoides, Lablab purpureus, Arachis pintoi, and Aeschynomene villosa] under the shade of an Eucalyptus grandis plantation submitted to thinning (40%) 8 years after planting in Anhembi, São Paulo (22°40'S, 48°10'W, altitude of 455 m). The experiment started in December 2008 and consisted of the comparison of the following four types of seed incorporation by light disc harrowing: (1) broadcast sowing without seed incorporation; disc harrowing before (2) or after (3) planting, and (4) disc harrowing before and after planting. Ninety days after planting, the number of legume plants/m2 and the percentage of ground cover by the plants varied between the treatments tested; however, the treatments had no effect on the dry matter accumulation of forage legumes. Disc harrowing before planting yielded superior results compared to the treatments without disc harrowing and disc harrowing after planting. At the end of the experimental period, the plots contained Arachis, Centrosema, Stylosanthes, and Pueraria. The dry matter accumulated by Centrosema corresponded to 73% of total dry matter yield of the plots. The participation of Arachis, Centrosema and Stylosanthes in final dry matter composition of the plots varied according to establishment method. The advantages of the use of species mixtures rather than monocultures in the understory of forest plantations were discussed.

Genetic diversity and population structure of pencil yam (Vigna lanceolata) (Phaseoleae, Fabaceae), a wild herbaceous legume endemic to Australia, revealed by microsatellite markers

Pencil yam (Vigna lanceolata Benth.) (Phaseoleae, Fabaceae) is a herbaceous legume endemic to Australia. A previous morphological study suggested that pencil yam is a complex species of two or more related taxa with seven distinct morphological types (morphotypes) and, thus, taxonomic revision is necessary. In this study, we assessed genetic diversity and determined the genetic structure of a pencil yam collection of 62 accessions from seven morphotypes using 18 microsatellite (simple sequence repeat) markers with the aim to provide information for taxonomic study. In total, 138 alleles were detected with a mean of 7.67 alleles per locus. Polymorphism information content per marker varied between 0.06 and 0.90 with a mean of 0.61, while the overall gene diversity was 0.62. Bayesian clustering, principal coordinate, and neighbor-joining analyses consistently revealed that these accessions are grouped into two subpopulations with difference in number of alleles, allelic richness, and gene diversity. The population structure was not related to either morphotype or geographical origin. Gene diversity of V. lanceolata was higher than that of wild Vigna radiata (L.) Wilczek and wild Vigna umbellata (Thunb.) Ohwi & Ohashi, comparable with that of wild Vigna mungo (L.) Hepper, Vigna exilis Tateishi & Maxted, and Vigna grandiflora (Prain) Tateishi & Maxted, and lower than that of wild Vigna angularis (Willd.) Ohwi & Ohashi. These results indicated that the taxonomy of V. lanceolata should be revised and that its gene diversity was moderate compared with the other wild Vigna species.

GROWTH AND MINERAL COMPOSITION OF TROPICAL FORAGE LEGUMES INOCULATED WITH RHIZOBIA

The objective of this paper was to evaluate the influence of indigenous and inoculated rhizobia and ammonium sulfate fertilizer on growth and mineral composition of the herbaceous legumes, Calopo (Calopogonium mucunoides), Ea Ea (Desmodium heterocarpon subsp. ovalifolium) and Kudzu (Pueraria phaseoloides), which are commonly used as forage plants and cover crops in Brazil. The treatments did not exhibit differences for total biomass of nodules. Lime application along with basic fertilization (without N) permitted nodulation and full growth and development of forages with native rhizobia.

Подходы к сохранению генофонда лекарственного растения Oxytropis lanata (Pall.) DC. (Fabaceae)

In order to preserve the gene pool of medicinal plant Oxytropis lanata (Pall.) DC. we analyzed allozyme polymorphism and identified reliable and informative marker enzyme systems of this species; also we studied the response of seeds to deep freezing in liquid nitrogen (–196 ºС). Population has an average level of polymorphism (P95 = 41,2 %, P99 = 52,9 %, A = 1,58, Ho = 0,158, He = 0,171) in general typical for herbaceous legumes, and can serve as a source of material for gene pool conservation of the species. Deep freezing has not led to the death of the seeds; it was marked stimulatory effect of ultralow temperatures, expressed as an acceleration of germination and sharp increase of germinability (98,6 ± 2,3 %) compared to the control (12,0 ± 3,5 %) that is associated with overcoming physical dormancy. There were no abnormalities in the development of seedlings from seeds passed cryopreservation.

Floristic composition and pasture condition of Aristida/Bothriochloa pastures in central Queensland. II. Soil and pasture condition interactions

Sustainable management of native pastures requires an understanding of what the bounds of pasture composition, cover and soil surface condition are for healthy pastoral landscapes to persist. A survey of 107 Aristida/Bothriochloa pasture sites in inland central Queensland was conducted. The sites were chosen for their current diversity of tree cover, apparent pasture condition and soil type to assist in setting more objective bounds on condition ‘states’ in such pastures. Assessors’ estimates of pasture condition were strongly correlated with herbage mass (r = 0.57) and projected ground cover (r = 0. 58), and moderately correlated with pasture crown cover (r = 0.35) and tree basal area (r = 0.32). Pasture condition was not correlated with pasture plant density or the frequency of simple guilds of pasture species. The soil type of Aristida/Bothriochloa pasture communities was generally hard-setting, low in cryptogam cover but moderately covered with litter and projected ground cover (30–50%). There was no correlation between projected ground cover of pasture and estimated ground-level cover of plant crowns. Tree basal area was correlated with broad categories of soil type, probably because greater tree clearing has occurred on the more fertile, heavy-textured clay soils. Of the main perennial grasses, some showed strong soil preferences, for example Tripogon loliiformis for hard-setting soils and Dichanthium sericeum for clays. Common species, such as Chrysopogon fallax and Heteropogon contortus, had no strong soil preference. Wiregrasses (Aristida spp.) tended to be uncommon at both ends of the estimated pasture condition scale whereas H. contortus was far more common in pastures in good condition. Sedges (Cyperaceae) were common on all soil types and for all pasture condition ratings. Plants identified as increaser species were Tragus australianus, daisies (Asteraceae) and potentially toxic herbaceous legumes such as Indigofera spp. and Crotalaria spp. Pasture condition could not be reliably predicted based on the abundance of a single species or taxon but there may be scope for using integrated data for four to five ecologically contrasting plants such as Themeda triandra with daisies, T. loliiformis and flannel weeds (Malvaceae).

A review of the leaf blotch miners of the genus Phyllonorycter Hübn. (Lepidoptera, Gracillariidae) in the Middle Volga Area, with a key to the species using morphological characters of the female genitalia

Data on the fauna and bionomics of the leaf blotch miner genus Phyllonorycter Hbn. of the Middle Volga Area are given. Twenty-eight species have been reared from leaf mines on more than 20 species of hosts in the investigated area. The harmful species Phyllonorycter medicaginella (infesting herbaceous legumes), Ph. apparella (the larvae heavily infest poplar leaves), and Ph. issikii are new to the region. Details of the female genitalia of Phyllonorycter are reported, and their characters are used for species diagnostics for the first time. A key to 13 Phyllonorycter species is given, with data on their host plants.

Environment, Harvest Regimen, and Ontogeny Change Lespedeza cuneata Condensed Tannin and Nitrogen

ABSTRACTCondensed tannins (CT) from sericea lespedeza [Lespedeza cuneata (Dumont de Courset) G. Don], a hardy and widely adapted forage legume, have potential for methane emission suppression, rumen protein bypass, gastrointestinal nematode suppression, and pest fly suppression in ruminants. Nitrogen (N) from this herbaceous legume can also be an important component of crude protein in ruminant diets. The concentrations and yields of CT and N, however, have not been studied across a wide range of environments, harvest regimens, or plant maturities. Our results from Texas and Georgia indicate that CT concentrations increased with rainfall, decreased with maturity, and were highly dependent on harvest regimen (P ≤ 0.05). Condensed tannin concentrations ranged (P ≤ 0.05) from 32.7 to 106.1 g CT kg−1 dry matter (DM) and CT DM yields from 274 to 771 kg ha−1 yr−1. Nitrogen concentrations ranged (P ≤ 0.05) from 14.6 to 28.4 g kg−1 DM and N DM yields from 46 to 231 kg ha−1 yr−1. If pellets or hay of sericea lespedeza are to be commercialized specifically for their CT and N content, analysis and labeling will be beneficial because of this variability.

Point of no return? Rehabilitating degraded soils for increased crop productivity on smallholder farms in eastern Zimbabwe

Soil degradation is a major threat to Southern Africa's agricultural production. Crops show generally weak responses to mineral fertilizers on degraded soils. A three-year study was conducted between 2009 and 2012 on smallholder farms in eastern Zimbabwe to explore entry points for rehabilitating degraded croplands using principles of integrated soil fertility management (ISFM) supported through farmers' local knowledge of soils. Participatory research approaches were first used to investigate farmers' understanding of soil degradation and the commonly used local diagnostic indicators. Farmers' determinants of degraded soils centered on crop performance, indicator weed species and soil physical attributes, and matched laboratory parameters. Overall, physical and chemical properties of the degraded soils were significantly lower than reported values for productive sandy soils in Zimbabwe. Evaluated on ten degraded field sites of corresponding catenary positions and similar slope, the main ISFM options involved nitrogen-fixing herbaceous legumes planted in the first year, with subsequent addition of cattle manure in the second year. In the third year, the influence of the ISFM options on maize productivity and changes in soil biological activity were then evaluated. Phosphorus was applied every year under each sequence. The controls were natural fallow and continuous maize. The treatments were randomly assigned to plots at each of the experimental sites and replicated across farms. Above-ground biomass carbon (C) and nitrogen (N) accumulation was 3038kgha−1 and 203kgha−1, respectively, under 1-year indigenous legume fallow (indifallow) against 518kgCha−1 and 14kgNha−1 under 1-year natural fallow. Two-year indifallow produced approximately three times the biomass N attained under the 2-year natural fallow. When all the treatments were planted to a maize test crop in the third year, herbaceous legume-based sequences showed the highest response to mineral fertilizer N compared with natural fallow-based sequences and continuous fertilized maize. A regression of maize yields against mineral N fertilizer showed a maximum yield of 2.5tha−1 under the herbaceous legume-based sequences against 1tha−1 under continuous fertilized maize and natural fallow-based options following addition of 120kgha−1 of mineral N fertilizer. ‘Green-start’, a Crotalaria juncea L. (sunnhemp)-based sequence, and ‘Indifallow-start 1’, an indigenous legume-based sequence, gave the highest microbial biomass C (MBC) of 243mgkg−1 soil compared with 187mgkg−1 soil under continuous maize. Microbial biomass N showed a similar trend. Under ‘Green-start’ and ‘Indifallow-start 1’, MBC to organic C ratio averaged 7; about one and half times more than under natural fallow-based sequences and continuous fertilized maize. Consistent with microbial biomass, soil carbon dioxide (CO2) emission under ‘Green-start’ and ‘Indifallow-start 1’ was 22% higher than under natural fallow-based sequences. Continuous maize treatments gave higher metabolic quotients (qCO2) than legume-based sequences, indicating a lower microbial efficiency under the former. We concluded that short-term restoration of productivity of degraded sandy soils should focus on high quality organic resource application and P fertilization to stimulate microbial activity and induce responses to mineral fertilizers. When coupled to P fertilization, herbaceous legume-based ISFM sequences provide a potential entry point for reversing soil degradation and offer opportunities for increasing crop productivity in dominant smallholder farming systems of Zimbabwe and other parts of Southern Africa.

Native Australian shrub legume species may provide an alternative feed source for livestock

The feed quality of a variety of native shrub and herbaceous legume species from the Riverina area of southern New South Wales was determined to provide an indication of their potential use in livestock grazing systems. Fifteen species were sampled from each of two locations (chiefly low fertility roadsides or travelling stock reserves) at four times within a 12-month period viz. August, November, February and May according to the most likely plant parts to be consumed by grazing animals for each species. Digestibility was estimated using an in vitro rumen fluid digestion assay and crude protein was estimated from nitrogen analysed using the Dumas combustion method. Digestible organic matter in the dry matter (DOMD) was greater than 550 g/kg dry matter (DM) for seven of the native legume species and was highest for Daviesia spp. (D. latifolia 696.2 ± 15.0, D. leptophylla × latifolia 642.5 ± 15.1 and D. leptophylla 622.7 ± 15.4), Glycine spp. (G. clandestina 628.2 ± 18.1, G. tabacina 621.9 ± 28.0 and G. canescens 580.4 ± 25.4) and Indigofera australis (617.8 ± 15.3). Crude protein content was greater than 80 g/kg DM for all species analysed, suggesting that these plants are able to fix nitrogen under low phosphorus fertility conditions. Studies examining grazing management as well as nitrogen fixation and nitrogen transfer to companion grasses are required in order to optimise the management of these plants in grazing systems.

Fatores edáficos determinando a ocorrência de leguminosas herbáceas em savanas amazônicas

Fatores edáficos vem sendo indicados como determinantes para a distribuição de comunidades de plantas na Amazônia. O objetivo deste estudo foi investigar quais fatores edáficos determinam a ocorrência de leguminosas herbáceas em savanas amazônicas. Para tanto, foi realizado um inventário da flora herbácea da família Leguminosae em 34 parcelas permanentes estabelecidas em duas áreas de savana de Roraima, norte da Amazônia brasileira. As espécies Chamaecrista desvauxii (24,9%), Aeschynomene histrix (15,7%) e Galactia jussiaeana (10,8%) foram as de maior índice de valor de importância. Todas com grande abundância e ampla distribuição. Os resultados indicaram baixa densidade ou ausência de indivíduos e espécies em parcelas estabelecidas em solos mal drenados (hidromórficos). Diversidade e riqueza de espécies tendeu a ser maior em habitats formados por solos bem drenados, mais férteis e com menor concentração de alumínio trocável. É sugerido que solos pobres e sazonalmente alagados reduzam as chances de ocorrência e afetem negativamente a riqueza/diversidade de leguminosas herbáceas nas áreas de savana de Roraima.

Biomass accumulation and chemical composition of Massai grass intercropped with forage legumes on an integrated crop-livestock-forest system

The objective was to evaluate the use of woody legumes (Albizia lebbeck, Cratylia argentea, Dipteryx Allata (Baru), a Leucaena hybrid (L. leucocephala + L. diversifolia), and Leucaena leucocephalacv. Cunningham) and herbaceous legumes (Arachis pintoi) intercropped with Panicum maximum cv. Massai, simultaneously implanted in a maize crop. The study made use of a randomized block experimental design with four replications. Assessments of biomass accumulation and forage nutritional value were made after the maize harvest, between June 2008 and October 2010. It was found that the residues of maize provided better growing conditions for Massai grass during the dry season. L. leucocephala cv. Cunningham and the Leucaena hybrid had the highest accumulation of all forage legumes evaluated, and provided the best nutritional value of all the arrangements tested. Of all woody legumes tested in this system, Leucaena was considered feasible for intercropping with Massai grass. The intercrop of perennial woody Baru with maize is not recommended. Albizia lebbeck and Cratylia argentea require further study, especially the yield assessment at different cutting intervals and cutting heights. Arachis pintoi had a low participation in the intercropping, showing greater performance over time, indicating slow thriving in this experimental condition.

Testing Agro-Ecological Adaptation of Improved Herbaceous Forage Legumes in South-Kivu, D.R. Congo

In tropical african countries where livestock is either reared in herds on natural grasslands or individuallly tethered to herds on natural or spontaneous vegetation, the productivity is low, especially during the dry season. Using improved forages could play an important role in both enhancing livestock production and improving soil fertility and preventing from soil erosion. Eleven herbaceous forage legumes previously tested in tropical South America and South Asia by CIAT were tested in South-Kivu, D. R. Congo. Across sites, Stylosanthes guianensis, Desmodium uncinatum, Centrosema molle and Canavalia brasiliensis had a highest yield, nowhere Vigna unguiculata adapted. Differencial plant adaptation occured, e.g. Clitoria ternatea being well adaptated only in the midlands with good soils, where the mean of dry mater leaf yield was higher. Farmer evaluation emphazied overall biomass production with preference in the highlands, farmers chose Desmodium uncinatum, Canavalia brasiliensis and Lablab purpureus 21603 and in the midlands Stylosanthes guianensis 11995 and Lablab purpureus 22759. Farmer evaluation confirmed the best yield fit herbaceous forage legumes.

Nitrogen contribution of some selected legumes to a sorghum based cropping system in the southern Guinea savanna of Nigeria

Field experiments to assess the Nitrogen (N) contribution of legumes to a sorghum based cropping system in the southern Guinea savanna of Nigeria were carried out during the 2004 and 2005 cropping seasons. The studies were conducted at the experimental station of the National Cereals Research Institute, Badeggi, Nigeria (09° 451 N, 06° 71 E). The experimental design was a split plot randomised complete block replicated three times. Species of herbaceous legumes (Canavalia ensiformis, Mucuna cochinchinesis), and grain legumes (Cowpea - [Vigna unguiculata] varieties L25 and IR48) as well as a fallow control were assigned to the main plots. N levels (0, 20, 40 and 60 kg/ha) were assigned to the sub plots. Plant residues of M. cochinchinesis and V. unguiculata -IR48 had the highest percent of N content (1.55 and 1.54% respectively), while C. ensiformis had the lowest (0.93%). Only the two cowpea varieties had C:N ratio of less than 30:1. The lignin and polyphenols content of all the legumes species were less than the critical levels of 15 and 4% respectively. The soil textural classification is of sandy loam with low initial N and cation exchange capacity. Application of N fertilizer to soils incorporated with legumes resulted in significantly higher mineral N (NO3 and NH4-N) accumulation than those without fertilizer N in both soil and sorghum N. Generally, higher mineral N was recorded in legume residue incorporated treatments than the control. Application of up to 40 kg N/ha to sorghum grown after incorporation of legumes except canavalia resulted in significantly higher yield of sorghum than those after fallow control. Key words: Nitrogen, Sorghum, canavalia, mucuna, cowpea.